Dear Student,
Answer to your question is as follows :
Potential resources are those resources which exist in a region and that can be utilised in the future.
Thus, Uranium is known as a potential resource when there is no existence of well known profit oriented method to extract it in low cost.
Uranium 235 is used in Power plants But So Far as all Possible Utilities Of Uranium may not be known To Us, this future Possibilities makes it potential.
Regards